Department of Resources and Environmental Engineering, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo Shinjuku-ku, Tokyo 169-8555, Japan.
Department of Resources and Environmental Engineering, Faculty of Science and Engineering, Waseda University, 3-4-1 Okubo Shinjuku-ku, Tokyo 169-8555, Japan; Retoca Laboratory LLC, 3-9-1 Maebarahigashi, Funabashi, Chiba 274-0824, Japan.
Waste Manag. 2021 Apr 15;125:58-66. doi: 10.1016/j.wasman.2021.01.008. Epub 2021 Mar 5.
To enable effective reuse and recycling processes of spent lithium-ion batteries (LiBs), here we develop a novel electrical method based on a high-voltage pulsed discharge to separate cathode particles and aluminum (Al) foil. A cathode particle sample was mechanically separated from a LiB, cut into 30-mm × 80-mm test pieces, and subjected to a high-voltage electrical pulse discharge from either end in water. At a voltage of 25 kV, 93.9% of the cathode particles separated from the Al foil. These particles were easily recovered by sieving at 2.36 mm because the Al foil retained its shape. Some Al contaminated the particles owing to generation of hot plasma and subsequent shock waves; however, the Al concentration in the recovered cathode particles was limited to 2.95%, which is low enough to allow for further cobalt and nickel recovery by hydrometallurgical processing. The results of heat balance calculations obtained from the current waveforms suggested that polyvinylidene fluoride, the main component of the adhesive in the cathode particle layers, melted and lost its adhesion through Joule heating of the Al foil at the maximum current of 19.0 kA at 25 kV. Almost 99% of the recovered cathode particles maintained their chemical composition and form after separation, and therefore could potentially be directly reused in LiBs.
为了实现废旧锂离子电池（LiB）的有效再利用和回收过程，我们在这里开发了一种基于高压脉冲放电的新型电气方法，用于分离阴极颗粒和铝（Al）箔。将 LiB 中的阴极颗粒样品从电池中机械分离出来，切成 30mm×80mm 的试件，然后在水中从两端进行高压电脉冲放电。在 25kV 的电压下，93.9%的阴极颗粒从 Al 箔上分离下来。这些颗粒很容易通过 2.36mm 的筛网回收，因为 Al 箔保持了其形状。由于产生热等离子体和随后的冲击波，一些 Al 污染了颗粒；然而，回收的阴极颗粒中的 Al 浓度限制在 2.95%以内，这足以通过湿法冶金处理进一步回收钴和镍。从电流波形获得的热平衡计算结果表明，聚偏二氟乙烯（PVDF）是阴极颗粒层中粘合剂的主要成分，在 25kV 时最大电流为 19.0kA 时，通过 Al 箔的焦耳加热而熔化并失去其附着力。分离后，几乎 99%的回收阴极颗粒保持其化学成分和形态，因此有可能直接在 LiB 中重复使用。
